Evaluate different ideas of signaling channels coming from research or other projects to see which ones are feasible to use. Aspects to evaluate: * soundness of the idea on real censorship scenarios * applicability to our needs * implementation maturity/easiness to implement The list of ideas and the place where the work will land is in the team wiki: https://gitlab.torproject.org/tpo/anti-censorship/team/-/wikis/Signaling-Channels